Sealing device

ABSTRACT

A sealing device includes a stationary side installation ring fixed to a stationary side member, a rotation side installation ring fixed to a rotation side member, a stationary side lip integrally provided on the stationary side installation ring and slidably contacting the rotation side installation ring, rotation side lips integrally formed on the rotation side installation ring and slidably contacting the stationary side installation ring, and a pulsar ring for a rotary encoder integrally formed on the rotation side installation ring, and magnetized to be multipolar. The rotation side installation ring includes first and second rotation side installation rings which are attached to each other. The rotation side lips are provided on the first rotation side installation ring at a relatively inner side. The pulsar ring is provided on the second rotation side installation ring at a relatively outer side.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. Ser. No. 12/225,510 filed Sep. 23, 2008,which is a national stage of the International Application No.PCT/JP2007/055174 filed Mar. 15, 2007, all of which claim priority toJapanese Patent Application No. 2006-098356 filed Mar. 31, 2006 and allof which are expressly incorporated by reference herein in theirentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sealing device for sealing an outerperiphery of a rotating body, and more particularly to a sealing deviceprovided with a pulsar ring of a rotary encoder for detecting arotation.

2. Description of the Conventional Art

FIG. 8 is a cross sectional view showing a sealing device for sealing abearing portion of a wheel suspension device for a motor vehicle bycutting it along a plane passing through an axis O. This kind of sealingdevice 100 is also called as a hub seal, and is structured to beinstalled between an outer ring 201 and an inner ring 202 of a bearing200 in order to prevent muddy water or the like from making an intrusioninto a bearing inner portion B from a bearing outer portion A.

In particular, the sealing device 100 shown in FIG. 8 is provided with ametal installation ring 101 pressure-inserted and fitted to an innerperipheral surface of the outer ring 201 of the bearing 200, and a sidelip 102 and a radial lip 103 integrally provided on the installationring 101, and the side lip 102 and the radial lip 103 are slidablybrought into close contact with a slinger 104 tightly fitted to an outerperipheral surface of the inner ring 202. Describing in detail, the sidelip 102 and the radial lip 103 are made of a rubber-like elasticmaterial, and are integrally bonded by vulcanization to the installationring 101 via a common base portion 106. The side lip 102 is slidablybrought into close contact with an inner side surface of a seal flangeportion 104 a of the slinger 104 by its tip end, and the radial lip 103at an inner peripheral side thereof is slidably brought into closecontact with an outer peripheral surface of a sleeve 104 b of theslinger 104 by an inner peripheral edge of its tip end directed to anouter side.

In this case, this kind of sealing device 100 includes a sealing deviceprovided with a rotary encoder for detecting a rotating speed and anangle of rotation of a shaft in addition, and a structure, for example,disclosed in-Japanese Unexamined Patent Publication No. 2004-93554 hasbeen conventionally known as a typical example. FIG. 9 is a crosssectional view showing the same kind of conventional sealing device withthe encoder as the in Japanese Unexamined Patent Publication No.2004-93554 by cutting it along a plane passing through an axis O.

In particular, the sealing device with the encoder disclosed in thepatent document 1 is structured such that, as shown in FIG. 9, a pulsarring 105, which is formed by a magnetic rubber and is magnetized to bemultipolar at a predetermined pitch in a circumferential direction, isintegrally provided on an outer surface of the seal flange portion 104 aof the slinger 104 in the sealing device 100 having the specificationshown in FIG. 8. In this case, the magnetic rubber is obtained by mixinga magnetic body into a rubber-like elastic material. Further, a magneticsensor 120 is arranged at an outer side of the pulsar ring 105 so as tooppose thereto in a non-rotating state, and the magnetic sensor 120constructs the rotary encoder together with the pulsar ring 105, andgenerates a pulse having a waveform corresponding to a change of amagnetic field caused by rotation of the pulsar ring 105 together withthe inner ring 202 of the bearing 200 so as to detect the rotation.

However, it is an actual condition that the pulsar ring 105 forconstructing the magnetic type rotary encoder is conventionally appliedonly to the slinger 104 of the sealing device 100, as shown in FIG. 9.

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

The present invention is made by taking the points mentioned above intoconsideration, and a main technical object of the present invention isto provide a sealing device in which a pulsar ring is applied to anotherrotating side member than a slinger, and the other technical object ofthe present invention is to provide a sealing device having an excellentsealing performance.

Means for Solving the Problem

As a means for effectively achieving the technical objects mentionedabove, in accordance with a first aspect of the present invention, thereis provided a sealing device comprising:

a stationary side installation ring tightly fitted and fixed to astationary side member;

a rotation side installation ring tightly fitted and fixed to a rotationside member;

a stationary side lip integrally provided on the stationary sideinstallation ring and slidably brought into close contact with therotation side installation ring by its tip end portion;

rotation side lips integrally formed on the rotation side installationring and slidably brought into close contact with the stationary sideinstallation ring by their tip end portions; and

a pulsar ring for a rotary encoder made of a synthetic resin orrubber-like elastic material mixed with a magnetic powder, integrallyformed on the rotation side installation ring, and magnetized to bemultipolar.

In accordance with a second aspect of the present invention, there isprovided a sealing device as recited in the first aspect, wherein acollar portion is provided in an extending manner on an outer peripheralportion of the pulsar ring so as to be positioned at an outer side thanthe rotation side lips and to be close and oppose to the stationary sidemember or the stationary side installation ring.

In accordance with a third aspect of the present invention, there isprovided a sealing device as recited in the first or second aspect,wherein the rotation side installation ring is constituted by first andsecond rotation side installation rings which are fitted and attached toeach other, the rotation side lips are provided on the first rotationside installation ring which is arranged at a relatively inner side, andthe pulsar ring is provided on an inner surface of the second rotationside installation ring which is constituted by a non-magnetic body andarranged at a relatively outer side.

In accordance with a fourth aspect of the present invention, there isprovided a sealing device as recited in the first or second aspect,wherein the rotation side installation ring is constituted by a firstrotation side installation ring which is provided with the rotation sidelips and is arranged at a relatively inner side, and a second rotationside installation ring which is provided with the pulsar ring and isarranged at a relatively outer side, and the second rotation sideinstallation ring is fitted and attached to a base portion of therotation side lips.

EFFECT OF THE INVENTION

In accordance with the sealing device on the basis of the first aspectof the present invention, since the rotation side lips and the pulsarring are integrally formed on the rotation side installation ring, it ispossible to suppress an enlargement of size caused by an addition of thepulsar ring, and the rotation side lips and the pulsar ring can besimultaneously formed on the rotation side installation ring.Accordingly, it is possible to suppress an increase of a manufacturingcost.

In accordance with the sealing device on the basis of the second aspectof the present invention, since the outer peripheral portion of thepulsar ring is provided in the extending manner with the collar portionwhich is close and opposes to the stationary side member or thestationary side installation ring at the outer side of the rotation sidelips, it is possible to achieve a spattering operation due tocentrifugal force and a labyrinth seal operation. Accordingly, it ispossible to improve a sealing performance. Further, since a widemagnetized surface can be secured, it is possible to obtain a stablemagnetic characteristic.

In accordance with the sealing device on the basis of the third aspectof the present invention, since a magnetic field of the pulsar ringprovided at the inner side of the second rotation side installation ringcan be detected by the magnetic sensor arranged at the outer side bymaking the second rotation side installation ring with a non-magneticbody, and the pulsar ring is protected by the second rotation sideinstallation ring, it is possible to make the magnetic field of thepulsar ring to be hardly affected by a disturbance from outside.

In accordance with the sealing device on the basis of the fourth aspectof the present invention, specification can be modified so as to includea rotary encoder by fitting and attaching a second rotation sideinstallation ring provided with a pulsar ring to a base portion ofrotation side lips in an existing sealing device, and it is possible toeasily select whether or not the specification includes a the rotaryencoder.

BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1 is a cross sectional view showing a sealing device in accordancewith a first embodiment of the present invention by cutting it along aplane passing through an axis O;

FIG. 2 is an explanatory view showing an example of a magnetizationpattern of a pulsar ring;

FIG. 3 is a cross sectional view showing a sealing device in accordancewith a second embodiment of the present invention by cutting it along aplane passing through an axis O;

FIG. 4 is a cross sectional view showing a sealing device in accordancewith a third embodiment of the present invention by cutting it along aplane passing through an axis O;

FIG. 5 is a cross sectional view showing a sealing device in accordancewith a fourth embodiment of the present invention by cutting it along aplane passing through an axis O;

FIG. 6 is a cross sectional view showing a sealing device in accordancewith a fifth embodiment of the present invention by cutting it along aplane passing through an axis O;

FIG. 7 is a cross sectional view showing a sealing device in accordancewith a sixth embodiment of the present invention by cutting it along aplane passing through an axis O;

FIG. 8 is a cross sectional view showing a sealing device for sealing abearing portion of a wheel suspension device for a motor vehicle bycutting it along a plane passing through an axis O; and

FIG. 9 is a cross sectional view showing a conventional sealing devicewith an encoder by cutting it along a plane passing through an axis O.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

A description will be given below of a preferable embodiment of thesealing device in accordance with the present invention with referenceto the accompanying drawings. FIG. 1 is a cross sectional view showing asealing device in accordance with a first embodiment of the presentinvention by cutting it along a plane passing through an axis O, andFIG. 2 is an explanatory view showing an example of a magnetizationpattern of a pulsar ring.

In FIG. 1, reference numeral 200 denotes a bearing rotatably supportinga wheel in a suspension device of a motor vehicle. A lot of steel balls203 are interposed between an outer ring 201 and an inner ring 202arranged concentrically in an inner periphery of the outer ring. In thiscase, the outer ring 201 does not rotate, and corresponds to thestationary side member described in the first aspect of the invention,and the inner ring 202 rotates together with a shaft (not shown), andcorresponds to the rotation side member described in the first aspect ofthe invention.

The sealing device 10 is constituted by a stationary side installationring 11 pressure-inserted and fitted to an inner peripheral surface ofan end portion of the outer ring 201 of the bearing 200, a rotation sideinstallation ring 12 tightly fitted and fixed to an outer peripheralsurface of the inner ring 202, an inner peripheral lip 13 integrallyprovided on the stationary side installation ring 11, a side lip 14 andan outer peripheral lip 15 integrally provided on the rotation sideinstallation ring 12, and a pulsar ring 17 for a rotary encoderintegrally formed on the rotation side installation ring 12 andmagnetized at a predetermined pitch in a circumferential direction. Inthis case, the inner peripheral lip 13 corresponds to the stationaryside lip described in the first aspect of the invention, and the sidelip 14 and the outer peripheral lip 15 correspond to the rotation sidelips described in the first aspect of the invention.

In detail, the stationary side installation ring 11 is manufactured bypunching and pressing a metal plate such as a steel plate or the like tohave an approximately L-shape (an illustrated cross sectional shape) ina shape obtained by cutting it along a plane passing through an axis O,and is constituted by an outer peripheral tube portion 11 apressure-inserted and fitted to an inner peripheral surface of the outerring 201, and an inward flange 11 b extending to an inner peripheralside from an end portion at a bearing inner portion B side thereof.

The rotation side installation ring 12 is also manufactured by punchingand pressing a metal plate such as a steel plate or the like to have anapproximately L-shape (an illustrated cross sectional shape) in a shapeobtained by cutting it along a plane passing through the axis O, and isconstituted by an inner peripheral tube portion 12 a pressure-insertedand fitted to an outer peripheral surface of the inner ring 202, and anoutward flange 12 b extending to an outer peripheral side from an endportion at a bearing outer portion A side thereof.

The inner peripheral lip 13 is integrally formed on the stationary sideinstallation ring 11 by positioning and setting the stationary sideinstallation ring 11 to which a vulcanization adhesive agent ispreviously applied, within a predetermined metal mold, then clamping themold, filling a rubber forming material into a forming cavity definedbetween the metal mold and the stationary side installation ring 11, andheating and pressurizing the material, and is structured such that abase portion 13 a is bonded by vulcanization to an inner diameterportion of the inward flange 11 b of the stationary side installationring 11, and extends in a taper shape toward an inner peripheral sidetherefrom and so as to be directed to an opposite side to the bearinginner portion B, and an inner periphery of a tip end portion is slidablybrought into close contact with an outer peripheral surface of the innerperipheral tube portion 12 a of the rotation side installation ring 12.

The side lip 14 and the outer peripheral lip 15 are integrally formed onthe rotation side installation ring 12 by positioning and setting therotation side installation ring 12 to which a vulcanization adhesiveagent is previously applied, within a metal mold (not shown), thenclamping the mold, filling a rubber forming material into a formingcavity defined between the metal mold and the rotation side installationring 12, and heating and pressurizing the material, and is structuredsuch that a common base portion 16 is bonded by vulcanization to anouter diameter portion of the outward flange 12 b of the rotation sideinstallation ring 12.

Among them, the side lip 14 is positioned at the outer peripheral sideof the inner peripheral lip 13, is formed in a conical tubular shapehaving a larger diameter at a tip end portion side, from an innerdiameter portion of a portion directed to an opposite side to thebearing outer portion A at the base portion 16, and is slidably broughtinto close contact with an inner surface of the inward flange 11 b ofthe stationary side installation ring 11 by a tip end portion thereof.Further, the outer peripheral lip 15 is positioned at an outerperipheral side of the side lip 14, rises up so as to bend in anapproximately C-shape in cross section from an outer diameter portion ofthe portion directed to the opposite side to the bearing outer portion Aat the base portion 16 to an outer peripheral side, and is slidablybrought into close contact with the inner peripheral surface of theouter peripheral tube portion 11 a of the stationary side installationring 11 by a tip end portion directed to the bearing outer portion Aside.

The pulsar ring 17 is bonded by vulcanization to the outer surface ofthe outward flange 12 b of the rotation side installation ring 12, ismade of a synthetic resin or rubber material mixed with magnetic powdersuch as a ferrite, a rare earth or an alnico for example, and isconstituted by a disc-shaped multipolar magnet in which S-poles andN-poles are alternately magnetized at a predetermined pitch in acircumferential direction, as shown in FIG. 2. Further, the pulsar ring17 can be structured so as to have a crank angle measurement startingpoint (not shown) for detecting a specific position such as a top deadcenter of a piston of an engine for example, by setting a portion (notshown) having a different magnetization pitch at one position in thecircumferential direction on the like.

Reference numeral 20 in FIG. 1 denotes a magnetic sensor. The magneticsensor 20 is arranged at one position in the circumferential directionat the bearing outer portion A, is fixed in a non-rotating state by afixing member (not shown), and is structured such that a detectingsurface 20 a is close to and opposed to an outer surface of the pulsarring 17 in an axial direction.

According to the sealing device 10 provided with the structure mentionedabove, the side lip 14 and the outer peripheral lip 15 rotatingintegrally with the inner ring 202 of the bearing 200 are slidablybrought into close contact with the inward flange 11 b and the outerperipheral tube portion 11 a of the non-rotating stationary sideinstallation ring 11, and the non-rotating inner peripheral lip 13 isslidably brought into close contact with the inner peripheral tubeportion 12 a of the rotation side installation ring 12 rotatingintegrally with the inner ring 202, thereby preventing a dust, muddywater or the like from making an intrusion into the bearing innerportion B from the bearing outer portion A, and also preventing thegrease from flowing out of the bearing inner portion B.

Further, since the pulsar ring 17 rotates integrally with the inner ring202, the multipolar magnetized N-poles and S-poles alternately passesthrough the front surface of the detecting surface 20 a of the magneticsensor 20 in the rotating direction, and a pulse-shaped signal having awaveform corresponding to change of a magnetic field is output from themagnetic sensor 20. Therefore, it is possible to measure an angle ofrotation and a number of rotations on the basis of a count of the pulse.

Further, in this embodiment, the pulsar ring 17 is integrally formed onthe outward flange 12 b of the rotation side installation ring 12together with the side lip 14 and the outer peripheral lip 15.Accordingly, it is possible to simultaneously form (bond byvulcanization) the pulsar ring 17, the side lip 14 and the outerperipheral lip 15 on the rotation side installation ring 12, by forminga cavity for forming the pulsar ring 17, and a cavity for forming theside lip 14 and the outer peripheral lip 15 in a common metal mold, andfilling a rubber molding material in the cavity for forming the side lip14 and the outer peripheral lip 15, and a molding material mixed withmagnetic powder in the cavity for forming the pulsar ring 17, at a timeof forming them.

Next, FIG. 3 is a cross sectional view showing a sealing device inaccordance with a second embodiment of the present invention by cuttingit along a plane passing through an axis O.

In this embodiment, the rotation side installation ring 12 isconstituted by first and second rotation side installation rings 121 and122 fitted and attached to each other, the side lip 14 and the outerperipheral lip 15 serving as the rotation side lips are provided on thefirst rotation side installation ring 121 which is arranged at arelatively inner side, the pulsar ring 17 is provided on the secondrotation side installation ring 122 which is arranged at a relatively anouter side, and an outer peripheral portion of the pulsar ring 17 formsa collar portion 17 a which is close to and opposes to an innerperipheral surface of the outer ring 201. The other portions arestructured basically in the same manner as the first embodiment (FIG. 1)described above.

In detail, the first rotation side installation ring 121 is manufacturedby punching and pressing a metal plate such as a steel plate or thelike, is formed in an approximately L-shape (an illustrated crosssectional shape) in a shape obtained by cutting along the plane passingthrough the axis O, and is constituted by an inner peripheral tubeportion 121 a in which an outer peripheral surface is slidably broughtinto close contact with an inner periphery of a tip end portion of theinner peripheral lip 13, and an outward flange 121 b extending to anouter peripheral side from an end portion at the bearing outer portion Aside thereof. Further, the common base portion 16 of the side lip 14 andthe outer peripheral lip 15 is bonded by vulcanization to an outerdiameter portion of the outward flange 121 b of the first rotation sideinstallation ring 121.

Further, the second rotation side installation ring 122 is manufacturedby punching and pressing a metal plate such as a steel plate or thelike, is formed in an approximately L-shape (an illustrated crosssectional shape) in a shape obtained by cutting it along the planepassing through the axis O, and is constituted by an inner peripheraltube portion 122 a in which an outer peripheral surface is fitted andattached integrally to the inner peripheral tube portion 121 a of thefirst rotation side installation ring 121, and an outward flange 122 bextending to an outer peripheral side from an end portion at the bearingouter portion A side and superposed with the outward flange 121 b of thefirst rotation side installation ring 121 in the axial direction.Further, the rotation side installation ring 12 is pressure-inserted andfitted to an outer peripheral surface of the inner ring 202 by the innerperipheral tube portion 122 a of the second rotation side installationring 122.

The pulsar ring 17 is bonded by vulcanization to the outer surface ofthe outward flange 122 b of the second rotation side installation ring122, and the collar portion 17 a formed on the outer periphery thereofis close to and opposed to the inner peripheral surface of the outerring 201 at an outer position than the side lip 14 and the outerperipheral lip 15.

Further, a seal protrusion 17 b extending from an outer diameter end ofthe outward flange 122 b of the second rotation side installation ring122 to an inner side (the first rotation side installation ring 121side) is formed on the outer peripheral portion of the pulsar ring 17.The seal protrusion 17 b achieves sealing between the fitted surfaces ofthe first rotation side installation ring 121 and the second rotationside installation ring 122 constructing the rotation side installationring 12, by being brought into close contact with the outward flange 121b of the first rotation side installation ring 121 or the base portion16 of the side lip 14 and the outer peripheral lip 15.

In accordance with the structure mentioned above, since the pulsar ring17 has a sealing function, it is possible to improve a sealingperformance in comparison with the first embodiment. In other words,since the pulsar ring 17 rotates in a state in which the collar portion17 a formed on the outer peripheral portion thereof is close and opposedto the inner peripheral surface of the outer ring 201 at the outerposition than the side lip 14 and the outer peripheral lip 15, it ispossible to shut out an intrusion of muddy water, a dust or the likefrom the bearing outer portion A on the basis of a spattering operationdue to centrifugal force. Further, the collar portion 17 a achieves alabyrinth effect by making an opposing distance to the inner peripheralsurface of the outer ring 201 small. Accordingly, it is possible tomaintain an excellent sealing performance in consequence of preventingdamage of the side lip 14 and the outer peripheral lip 15 caused by theintrusion of muddy water, a dust or the like.

Further, since a width in a radial direction of the pulsar ring 17 isenlarged by the collar portion 17 a, and a wide magnetized surface canbe secured, it is possible to obtain a stable magnetic characteristic.

Next, FIG. 4 is a cross sectional view showing a sealing device inaccordance with a third embodiment of the present invention by cuttingit along a plane passing through an axis O.

In this embodiment, in the first and second rotation side installationrings 121 and 122 constructing the rotation side installation ring 12,the second rotation side installation ring 122 which is arranged at arelatively outer side is constituted by a non-magnetic body, and thepulsar ring 17 is bonded by vulcanization integrally to the innersurface of the outward flange 122 b of the second rotation sideinstallation ring 122. The other portions are basically provided withthe same structures as the second embodiment (FIG. 3) described above.

In other words, as shown in FIG. 4, the pulsar ring 17 is provided in astate of being sandwiched between the outward flange 121 b of the firstrotation side installation ring 121 and the outward flange 122 b of thesecond rotation side installation ring 122, and the collar portion 17 aformed on the outer peripheral portion of the pulsar ring 17 is closeand opposed to the end portion of the outer peripheral tube portion 11 aof the stationary side installation ring 11 at an outer position thanthe side lip 14 and the outer peripheral lip 15. Accordingly, thedetecting surface 20 a of the magnetic sensor 20 arranged at the bearingouter portion A is close and opposed to the outer surface of the outwardflange 122 b of the second rotation side installation ring 122 in theaxial direction, however, the magnetic field of the pulsar ring 17 atthe inner side thereof can be detected by forming the second rotationside installation ring 122 with a non-magnetic body.

Further, since the inner surface of the pulsar ring 17 is brought intoclose contact with the seal protrusion 16 a formed on the base portion16 of the side lip 14 and the outer peripheral lip 15, it is possible toachieve sealing between the fitted surfaces of the first rotation sideinstallation ring 121 and the second rotation side installation ring 122constructing the rotation side installation ring 12.

In accordance with the structure mentioned above, in addition to theeffect obtained by the second embodiment (FIG. 3), since the pulsar ring17 is protected by the outward flange 122 b of the second rotation sideinstallation ring 122, there can be obtained such an advantage that themagnetic field of the pulsar ring 17 is hardly affected by a disturbancefrom outside.

Next, FIG. 5 is a cross sectional view showing a sealing device inaccordance with a fourth embodiment of the present invention by cuttingit along a plane passing through an axis O.

In this embodiment, the second rotation side installation ring 122,which is arranged at a relatively outer side, of the rotation sideinstallation ring 12 is fitted and attached to the outer peripheralsurface of the base portion 16 of the side lip 14 and the outerperipheral lip 15 by the outer peripheral tube portion 122 c, an innerperipheral portion 17 c of the pulsar ring 17 integrally provided on thesecond rotation side installation ring 122 is brought into close contactwith the outer peripheral surface of the end portion of the inner ring202, and the first rotation side installation ring 121, which isarranged at a relatively inner side, is pressure-inserted and fitted tothe outer peripheral surface of the inner ring 202 of the bearing 200 bythe inner peripheral tube portion 121 a thereof. The other portions arestructured basically in the same manner as the second embodiment (FIG.3) described above.

In detail, the second rotation side installation ring 122 ismanufactured by punching and pressing a metal plate such as a steelplate or the like, is formed approximately in an L-shape (an illustratedcross sectional shape) in a shape obtained by cutting it along a planepassing through the axis O, as shown in FIG. 5, and is constituted by anouter peripheral tube portion 122 c fitted and attached to an outerperipheral surface of the base portion 16 of the side lip 14 and theouter peripheral lip 15, and an inward flange 122 d extending to aninner peripheral side from an end portion at the bearing outer portion Aside. In the outer peripheral tube portion 122 c, there is formed a bentportion 122 e for making a part of the base portion 16 thrust thereintoso as to increase fitting force.

In accordance with the structure mentioned above, in addition to theeffect obtained by the second embodiment (FIG. 3), there can be obtainedsuch an advantage that it is easy to select whether or not thespecification of the sealing device 10 includes a rotary encoder. Thereason is that the first rotation side installation ring 121 of therotation side installation ring 12 is not fitted and attached to theinner ring 202 of the bearing 200 via the second rotation sideinstallation ring 122, but the second rotation side installation ring122 integrally having the pulsar ring 17 is fitted and attached to theouter peripheral surface of the base portion 16 of the side lip 14 andthe outer peripheral lip 15 by the outer peripheral tube portion 122 cthereof.

Further, since a width in the radial direction of the pulsar ring 17 isenlarged in the outer diametrical direction by the collar portion 17 a,and is also enlarged to the outer peripheral surface position of the endportion of the inner ring 202 in the inner diametrical direction, a widemagnetized surface can be secured, and it is possible to obtain a stablemagnetic characteristic.

In this case, various shapes can be considered as a shape of the bentportion 122 e for preventing the second rotation side installation ring122 from coming off, for example, a convex shape thrusting into theouter peripheral surface of the base portion 16 of the side lip 14 andthe outer peripheral lip 15, in addition to the illustrated shape.

Next, FIG. 6 is a cross sectional view showing a sealing device inaccordance with a fifth embodiment of the present invention by cuttingit along a plane passing through an axis O.

The sealing device 10 in accordance with this embodiment is structuredsuch that the second rotation side installation ring 122 in the fourthembodiment (FIG. 5) mentioned above is constituted by a non-magneticbody, and the pulsar ring 17 is bonded by vulcanization integrally to aninner surface of an inward flange 122 d of the second rotation sideinstallation ring 122. Accordingly, since the outer peripheral side ofthe pulsar ring 17 is covered by the outer peripheral tube portion 122 cof the second rotation side installation ring 122, the pulsar ring 17 isstructured such that the collar portion 17 a as shown in FIG. 5 does notexist. The other structures are basically the same as the fourthembodiment (FIG. 5).

In other words, as shown in FIG. 6, the pulsar ring 17 is provided in astate of being sandwiched between the outward flange 121 b of the firstrotation side installation ring 121 and the inward flange 122 d of thesecond rotation side installation ring 122. Accordingly, the detectingsurface 20 a of the magnetic sensor 20 arranged at the bearing outerportion A is close and opposed to the outer surface of the inward flange122 d of the second rotation side installation ring 122 in the axialdirection, however, the magnetic field of the pulsar ring 17 existing atthe inner side thereof can be detected by forming the second rotationside installation ring 122 with a non-magnetic material in the samemanner as the third embodiment (FIG. 4) described above.

Further, in this embodiment, since the first rotation side installationring 121 of the rotation side installation ring 12 is fitted andattached to the inner ring 202 of the bearing 200 by the innerperipheral tube portion 121 a in the same manner as the fourthembodiment (FIG. 5), and the second rotation side installation ring 122integrally having the pulsar ring 17 is fitted and attached to the outerperipheral surface of the base portion 16 of the side lip 14 and theouter peripheral lip 15 by the outer peripheral tube portion 122 cthereof, it is possible to easily select whether or not thespecification of the sealing device 10 includes a rotary encoder.

Next, FIG. 7 is a cross sectional view showing a sealing device inaccordance with a sixth embodiment of the present invention by cuttingit along a plane passing through an axis O.

In accordance with this embodiment, the rotation side installation ring12 is structured such that the first rotation side installation ring 121integrally having the side lip 14 and the outer peripheral lip 15 isfitted and attached to the outer peripheral portion of the secondrotation side installation ring 122 integrally having the pulsar ring17, and the inner peripheral lip 13 bonded by vulcanization to the innerdiameter portion of the inward flange 11 b of the stationary sideinstallation ring 11 is slidably brought into close contact with theouter peripheral surface of the inner peripheral tube portion 122 a ofthe second rotation side installation ring 122 pressure-inserted andfitted to the outer peripheral surface of the inner ring 202 of thebearing 200. The other portions are structured basically in the samemanner as the second embodiment (FIG. 3) or the fourth embodiment (FIG.5) described above.

In detail, the first rotation side installation ring 121 is manufacturedby punching and pressing a metal plate such as a steel plate or thelike, and is formed approximately in an L-shape (an illustrated crosssectional shape) in a shape obtained by cutting it along the planepassing through the axis O, that is, constituted by the outward flange121 b, on which the common base portion 16 of the side lip 14 and theouter peripheral lip 15 is bonded by vulcanized, and the innerperipheral tube portion 121 c which is bent toward the bearing outerportion A side from the inner periphery thereof.

Further, the second rotation side installation ring 122 is manufacturedby punching and pressing a metal plate such as a steel plate or thelike, is formed approximately in a C-shape (an illustrated crosssectional shape) in a shape obtained by cutting it along the planepassing through the axis O, and is constituted by an inner peripheraltube portion 122 a which is pressure-inserted and fitted to the outerperipheral surface of the inner ring 202 of the bearing 200 by its innerperipheral surface, a radial portion 122 f which extends to an outerperipheral side from an end portion at the bearing outer portion A sidethereof, and an outer peripheral tube portion 122 g which extends towardthe bearing inner space B side from an outer peripheral end thereof.Further, the inner peripheral tube portion 121 c of the first rotationside installation ring 121 is pressure-inserted and fitted to an innerperiphery of the outer peripheral tube portion 122 g of the secondrotation side installation ring 122, whereby the first and secondrotation side installation rings 121 and 122 are integrated with eachother so as to construct the rotation side installation ring 12.

Further, the pulsar ring 17 is bonded by vulcanization to an outersurface of the radial portion 122 f of the second rotation sideinstallation ring 122, and the collar portion 17 a formed on an outerperiphery thereof is close and opposed to an inner peripheral surface ofthe outer ring 201 at an outer position than the side lip 14 and theouter peripheral lip 15.

In accordance with the structure mentioned above, it is possible toachieve the same effects as the second embodiment (FIG. 3) or the fourthembodiment (FIG. 5) described above.

INDUSTRIAL APPLICABILITY

The present invention can be utilized as a sealing device provided witha pulsar ring of a rotary encoder for detecting a rotation.

1. A sealing device comprising: a stationary side installation ringtightly fitted and fixed to a stationary side member; a rotation sideinstallation ring tightly fitted and fixed to a rotation side member; astationary side lip integrally provided on the stationary sideinstallation ring and slidably brought into close contact with therotation side installation ring by its tip end portion; rotation sidelips integrally formed on the rotation side installation ring andslidably brought into close contact with the stationary sideinstallation ring by their tip end portions; and a pulsar ring for arotary encoder made of a synthetic resin or rubber-like elasticmaterial, mixed with magnetic powder, integrally formed on the rotationside installation ring, and magnetized to be multipolar, wherein therotation side installation ring is constituted by first and secondrotation side installation rings which are fitted and attached to eachother, the rotation side lips are provided on the first rotation sideinstallation ring arranged at a relatively inner side, and the pulsarring is provided on the second rotation side installation ring arrangedat a relatively outer side.
 2. The sealing device as claimed in claim 1,wherein the pulsar ring is provided on an outer surface of the secondrotation side installation ring.
 3. The sealing device as claimed inclaim 1, wherein the second rotation side installation ring isconstituted by a non-magnetic body, and the pulsar ring is provided onan inner surface of the second rotation side installation ring.
 4. Thesealing device as claimed in claim 2, wherein the first rotation sideinstallation ring is constituted by a first inner peripheral tubeportion in which an outer peripheral surface is slidably brought intoclose contact with an inner periphery of the stationary side lip, and afirst flange extending outwardly from one end portion of the first innerperipheral tube portion, the second rotation side installation ring isconstituted by a second inner peripheral tube portion in which an outerperipheral surface is fitted and attached integrally to the first innerperipheral tube portion of the first rotation side installation ring,and a second flange extending outwardly from one end portion of thesecond inner peripheral tube portion and superposed with the firstflange of the first rotation side installation ring in an axialdirection, the pulsar ring is bonded by vulcanization to an outersurface of the second flange of the second rotation side installationring, and the rotation side installation ring is pressure-inserted andfitted to an outer peripheral surface of the rotation side member by thesecond inner peripheral tube portion of the second rotation sideinstallation ring.
 5. The sealing device as claimed in claim 3, whereinthe first rotation side installation ring is constituted by a firstinner peripheral tube portion in which an outer peripheral surface isslidably brought into close contact with an inner periphery of thestationary side lip, and a first flange extending outwardly from one endportion of the first inner peripheral tube portion, the second rotationside installation ring is constituted by a second inner peripheral tubeportion in which an outer peripheral surface is fitted and attachedintegrally to the first inner peripheral tube portion of the firstrotation side installation ring, and a second flange extending outwardlyfrom one end portion of the second inner peripheral tube portion andsuperposed with the first flange of the first rotation side installationring in an axial direction, the pulsar ring is bonded by vulcanizationto an outer surface of the second flange of the second rotation sideinstallation ring, and the rotation side installation ring ispressure-inserted and fitted to an outer peripheral surface of therotation side member by the second inner peripheral tube portion of thesecond rotation side installation ring.
 6. The sealing device as claimedin claim 2, wherein a collar portion is provided in an extending manneron an outer peripheral portion of the pulsar ring so as to be close toand opposed to the stationary side member at an outer position than therotation side lips.
 7. The sealing device as claimed in claim 3, whereina collar portion is provided in an extending manner on an outerperipheral portion of the pulsar ring so as to be close to and opposedto the stationary side member at an outer position than the rotationside lips.
 8. The sealing device as claimed in claim 4, wherein a collarportion is provided in an extending manner on an outer peripheralportion of the pulsar ring so as to be close to and opposed to thestationary side member at an outer position than the rotation side lips.9. The sealing device as claimed in claim 5, wherein a collar portion isprovided in an extending manner on an outer peripheral portion of thepulsar ring so as to be close to and opposed to the stationary sidemember at an outer position than the rotation side lips.